There may be no single cause of bipolar disorder (aka manic depression). Instead, research indicates the causes of bipolar disorder are probably a combination of biochemical, genetic and environmental factors that may trigger and perpetuate the chemical imbalances in the brain.
Net worth: $829 million. Telecommunications mogul Strive Masiyiwa is widely regarded as the richest man in Zimbabwe and is one of the richest men in Africa with a net worth of more than US$800 million.
Shona is the most spoken language in Zimbabwe, with over 10 million speakers in a population of over 14 million. It is Bantu language from the Bantu/Nguni family of languages, and has speakers in Botswana and Mozambique. It is the principle language of Zimbabwe, along with Ndebele and English.